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Pictures: '99 Tunnel Mod, Sparco Seat Mounts

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#21
RussMcB

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From what i could tell in the pics, the right side bracket and backing plate are bolted through that east street panel. If that panel was welded in id say no problem but you are really just relying on those few rivets to hold that panel in which i dont think are adequate. Not to mention your harness eyelet is on the seat bracket which is a bad idea and relying on those rivets as well. I have mounted probably over a hundred miata seats and i rarely have to remove the stock front mounting bracket, i think it really strengthens the floor.

 

I like those east street panels and im not knocking your work, i just think seats need to be strongly secured for the belts to serve their purpose.

 

Jedd, thanks for your input.  One of the reasons I posted was to give people some options to consider and discuss.  As we build our cars, there are lots of decisions and compromises, all with pros and cons.

 

I don't disagree with your comments, but please understand two things:

1) the two stud plates are not individual, stand alone fasteners.  On each side they are 2' long.

2) Nothing is solely bolted to the riveted tunnel panel.  The load is spread over the entire 2', which, on the right side, is mostly a combination of the stock floor board and the tunnel panel.

 

Admittedly, I can't provide numbers to prove what force it would take to rip the mounts out of the car, but it would be substantial.  I'm convinced these stud strips are stronger than four individual fasteners (even with 4"x4" backing plates).

 

I agree that leaving the cross brace in would strengthen the floor but I felt it was a worthwhile compromise.

 

Lastly, I'm not thrilled with my right side lap belt attachment, but it is stronger than if I had attached the eyebolt into the thinner tunnel sheet metal.  You can't see it in the pictures, but there is some reinforcement that helps put some of the force in-line (tension rather than just shear).


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#22
Blake Thompson

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Just about finished installing mine but the welder ran out of wire.  I have this bruise on my chest that for the whole day I couldn't figure out what it was from... till that night, I leaned back over my nascar bars to begin cutting again and there it is.  4-5 hours of draping myself over steel bars took its toll.

 

I figure I'll have 8 hours into this install by the time I'm done.  I imagine a shop would do that in less than half the time, I am easily distracted.

 

After installing and seeing how much of the car is cut into the put the panel in place I can't imagine why someone would use pop rivets instead of welding.  I really think you are asking for a disaster.


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#23
RussMcB

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After installing and seeing how much of the car is cut into the put the panel in place I can't imagine why someone would use pop rivets instead of welding.  I really think you are asking for a disaster.

Disaster?  That's a strong word.  What do you think might happen?

 

I wonder if you removed a lot more metal than I did.  Take a look at my first picture.  I only removed enough to allow the new panel to fit.  The panel is a lot bigger than the hole it is covering.

 

http://mazdaracers.c...ea-mount-humps/


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#24
davew

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Yes Blake, it can be done much faster.

 

I have used many of these, they are great. But I would never just rivet them in. Even if you don't consider it structural due to the installation of the roll cage, it is definately important to the security of the seat mounting. The rivets should be temporary for allignment purposes. But you really do need to weld it properly

 

Dave


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#25
Blake Thompson

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Yes Blake, it can be done much faster.

 

I have used many of these, they are great. But I would never just rivet them in. Even if you don't consider it structural due to the installation of the roll cage, it is definately important to the security of the seat mounting. The rivets should be temporary for allignment purposes. But you really do need to weld it properly

 

Dave

 

hey dave, do youse guys remove the drivetrain to weld the inside?  I think the trans tail piece might be in the way, but the drivetrain is out of my car and still in Steph's


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